U.S. patent application number 15/762981 was filed with the patent office on 2019-10-03 for lighting device.
This patent application is currently assigned to LG INNOTEK CO., LTD.. The applicant listed for this patent is LG INNOTEK CO., LTD.. Invention is credited to Chang Hyuk IM, Cheon Joo KIM, Hwa Young KIM, Ki Woong KIM, Young Kuk KWAK.
Application Number | 20190301719 15/762981 |
Document ID | / |
Family ID | 58386428 |
Filed Date | 2019-10-03 |
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United States Patent
Application |
20190301719 |
Kind Code |
A1 |
IM; Chang Hyuk ; et
al. |
October 3, 2019 |
LIGHTING DEVICE
Abstract
A lighting device according embodiments comprises: a housing
including first and second back covers having arcuate inner
surfaces; a recess opened to the lower portions of the first and
second back covers; a transparent sheet disposed in a diagonal line
configuration on the recesses of the first and second back covers;
a light emitting module between the recesses of the first and
second back covers; a heat dissipating body on which the light
emitting module is disposed; and a first reflective sheet
reflecting light onto inner surfaces of the first and second back
covers, wherein the heat dissipating body includes a heat
dissipation part having the first and second light emitting modules
disposed thereon, and a reflective part disposed between the heat
dissipating part and the bottom portion of the transparent sheet,
and the first reflective sheet has multiple reflective
surfaces.
Inventors: |
IM; Chang Hyuk; (Seoul,
KR) ; KWAK; Young Kuk; (Seoul, KR) ; KIM; Ki
Woong; (Seoul, KR) ; KIM; Cheon Joo; (Seoul,
KR) ; KIM; Hwa Young; (Seoul, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
LG INNOTEK CO., LTD. |
Seoul |
|
KR |
|
|
Assignee: |
LG INNOTEK CO., LTD.
Seoul
KR
|
Family ID: |
58386428 |
Appl. No.: |
15/762981 |
Filed: |
September 22, 2016 |
PCT Filed: |
September 22, 2016 |
PCT NO: |
PCT/KR2016/010571 |
371 Date: |
March 23, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F21V 7/09 20130101; F21V
7/24 20180201; F21V 7/0008 20130101; F21V 7/06 20130101; F21K 9/66
20160801; F21K 9/62 20160801; F21V 3/062 20180201; F21V 15/01
20130101; F21V 7/0041 20130101; F21V 17/10 20130101; F21Y 2103/10
20160801; F21V 7/04 20130101; F21V 15/013 20130101; F21V 17/16
20130101; F21Y 2115/10 20160801; F21K 9/65 20160801; F21S 8/026
20130101; F21V 29/70 20150115; F21S 2/00 20130101 |
International
Class: |
F21V 29/70 20060101
F21V029/70; F21K 9/66 20060101 F21K009/66; F21V 7/00 20060101
F21V007/00; F21V 3/06 20060101 F21V003/06; F21V 7/09 20060101
F21V007/09; F21V 7/06 20060101 F21V007/06 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 25, 2015 |
KR |
10-2015-0136317 |
Sep 25, 2015 |
KR |
10-2015-0136321 |
Sep 25, 2015 |
KR |
10-2015-0136323 |
Sep 25, 2015 |
KR |
10-2015-0136324 |
Claims
1. A lighting device comprising: a housing having a first back
cover and a second back cover on both sides in a first axial
direction; a first recess in which a lower portion of the first
back cover is opened; a second recess in which a lower portion of
the second back cover is opened; a heat radiator disposed between
the first and second recesses in a second axial direction
perpendicular to the first axial direction at a lower portion of
the housing; a first light-emitting module having a plurality of
light emitting diodes (LEDs) in a first region of the heat radiator
corresponding to the first recess; a second light-emitting module
having a plurality of LEDs in a second region of the heat radiator
corresponding to the second recess; a first light-transmitting
sheet disposed at the first recess so as to be inclined with
respect to the first axial direction and configured to diffuse
light emitted from the first light-emitting module; a second
light-transmitting sheet disposed at the second recess so as to be
inclined with respect to the first axial direction and configured
to diffuse light emitted from the second light-emitting module; and
a front cover configured to support a lower portion of the heat
radiator and lower end portions of the first and second
light-transmitting sheets, wherein the front cover comprises a
fixing frame protruding to a direction of the heat radiator at the
lower portion of the heat radiator, and a cover plate extending to
a direction of the lower end portions of the first and second
light-transmitting sheets from the fixing frame, and wherein an
internal angle between the first light-transmitting sheet and the
second light-transmitting sheet is less than 180 degrees.
2. The lighting device of claim 1, wherein the heat radiator
comprises: a first heat dissipation part in which the first
light-emitting module is disposed, a second heat dissipation part
in which the second light-emitting module is disposed, a first
reflector extending from the first heat dissipation part to the
lower end portion of the first light-transmitting sheet, a second
reflector extending from the second heat radiating part to the
lower end portion of the second light-transmitting sheet, and light
leakage-preventing protrusion protruding from lower end portions of
the first and second reflectors to a direction of the cover plate
and facing parts of the first and second light-transmitting
sheets.
3. The lighting device of claim 2, wherein an upper surface or a
lower surface of the cover plate has a curved surface or an
inclined surface.
4. The lighting device of claim 1, wherein the cover plate has a
concave-convex structure at an outer lower portion thereof.
5. The lighting device of claim 2, wherein the cover plate has a
step structure at an outer side portion, and the step structure
corresponds to the light leakage-preventing protrusions of the
first and second reflectors of the heat radiator.
6. The lighting device of claim 1, comprising: first and second
latching jaws protruding from both sidewalls in the second axial
direction in each of the first and second recesses; a first
latching protrusion disposed long at an inner side of the first
recess in the second axial direction; and a second latching
protrusion disposed long at an inner side of the second recess in
the second axial direction, wherein the first light-transmitting
sheet is disposed on the first and second latching jaws of the
first recess and on the first latching protrusion, and the second
light transmitting-sheet is disposed on the first and second
latching jaws of the second recess and on the second latching
protrusion.
7. The lighting device of claim 5, wherein each of the first and
second latching jaws comprises first and second supporting portions
configured to support both ends of the first and second
light-transmitting sheets in the second axial direction, and a
light leakage-preventing portion protruding from the first and
second supporting portions and facing side surfaces of the lower
end portions of the first and second light-transmitting sheets.
8. The lighting device of claim 7, wherein the first and second
light-transmitting sheets are inclined with respect to an optical
axis of the light emitting diodes (LEDs) of the first and second
light-emitting modules.
9. The lighting device of claim 1, wherein the front cover
comprises a plastic material.
10. The lighting device of claim 2, comprising: a first reflective
sheet adjacent to the first and second light-emitting modules in
inner side surfaces of the first and second recesses; and a second
reflective sheet disposed between the first reflective sheet and
upper end portions of the first and second light-transmitting
sheets in the inner side surfaces of the first and second
recesses.
11. The lighting device of claim 10, wherein the first and second
reflectors comprise a third reflective sheet having a plurality of
reflective surfaces having different radii of curvature
thereon.
12. The lighting device of claim 10, wherein the first reflective
sheet comprises a regular reflection material and the second
reflective sheet comprises an irregular reflection material.
13. The lighting device of claim 12, wherein the first reflective
sheet has a plurality of reflective surfaces and a radius of
curvature of the plurality of reflective surfaces increases as a
distance from a center of the LEDs of the first and second
light-emitting modules becomes farther.
14. The lighting device of claim 10, wherein a boundary portion
between the first and second reflective sheets is a highest point
portion of the first and second recesses.
15. The lighting device of claim 11, wherein the third reflective
sheet comprises a regular reflection material or an irregular
reflection material, and the third reflective sheet is disposed
further adjacent to the LEDs of the first and second light-emitting
modules than the first reflective sheet.
16. The lighting device of claim 11, wherein the third reflective
sheet overlaps with the front cover in a vertical direction and is
disposed below the optical axis of the LEDs of the first and second
light-emitting modules.
17. The lighting device of claim 10, wherein the first and second
light-transmitting sheets comprises a diffusion sheet and are
located at a higher position away from the light emitting diodes of
each of the first and second light-emitting modules, and wherein
the first and second reflective sheets are disposed above an
optical axis of the LEDs of the first and second light-emitting
modules.
18. The lighting device of claim 10, wherein each of the first and
second recesses has a parabolic shape.
19. The lighting device of claim 18, wherein the first and second
light-emitting modules comprise a circuit board on which the LEDs
are disposed on the first and second heat dissipation parts,
wherein the circuit board is disposed on a vertical surface of the
first and second heat dissipation parts in the second axial
direction, and the first and second light-transmitting sheets are
inclined with respect to the optical axis of the LEDs of the first
and second light-emitting module in a range of 9 to 13 degrees, and
wherein the first and second reflective sheets are disposed above
the optical axis of the LEDs of the first and second light-emitting
module.
20. (canceled)
21. A lighting device comprising: a housing having a first back
cover and a second back cover on both sides in a first axial
direction; a first recess in which a lower portion of the first
back cover is opened; a second recess in which a lower portion of
the second back cover is opened; a heat radiator disposed between
the first and second recesses in a second axial direction
perpendicular to the first axial direction at a lower portion of
the housing; a first light-emitting module having a plurality of
light emitting diodes (LEDs) in a first region of the heat radiator
corresponding to the first recess; a second light-emitting module
having a plurality of LEDs in a second region of the heat radiator
corresponding to the second recess; a first light-transmitting
sheet disposed at the first recess so as to be inclined with
respect to the first axial direction and configured to diffuse
light emitted from the first light-emitting module; a second
light-transmitting sheet disposed at the second recess so as to be
inclined with respect to the first axial direction and configured
to diffuse light emitted from the second light-emitting module; and
a front cover configured to support a lower portion of the heat
radiator and lower end portions of the first and second
light-transmitting sheets, wherein the front cover comprises a
fixing frame protruding to a direction of the heat radiator at the
lower portion of the heat radiator, and a cover plate extending to
a direction of the lower end portions of the first and second
light-transmitting sheets from the fixing frame, wherein an
internal angle between the first light-transmitting sheet and the
second light-transmitting sheet is less than 180 degrees, wherein a
portion of the first light-transmitting sheet faces the plurality
of LEDs of the first light-emitting module, and wherein a portion
of second light-transmitting sheet faces the plurality of LEDs of
the second light-emitting module.
Description
TECHNICAL FIELD
[0001] An embodiment relates to a lighting device.
BACKGROUND ART
[0002] In general, a lighting device using a LED generates a high
heat when the lighting device is turned on. This heat results in
lowering a life of a lamp and various components supporting the
same.
[0003] When the lighting device using the LED is used, a hot spot
may occur. There is a need for a lighting structure to reduce such
a hot spot and to prevent glare.
DISCLOSURE
Technical Problem
[0004] An embodiment provides a lighting device for a flat
panel.
[0005] An embodiment provides a lighting device having a light
emitting diode (LED).
[0006] An embodiment provides a lighting device for preventing
glare.
[0007] An embodiment provides a lighting device, which reflects on
both side light of a plurality of LEDs and uniformly irradiates the
light through a light-transmitting sheet.
[0008] An embodiment provides a lighting device in which a
non-uniform light distribution is improved by side light emitted
from the LED in a specific region of the light-transmitting
sheet.
[0009] An embodiment provides a lighting device having a front
cover configured to cover a heat radiator to which a light-emitting
module is coupled in a central axis direction of a housing.
[0010] An embodiment provides a lighting device having a front
cover configured to support a lower end portion of the
light-transmitting sheet disposed on both sides of a center of the
housing.
[0011] An embodiment provides a lighting device having a latching
jaw, which faces one side surface of the light-transmitting sheet
on both sidewalls of an inner side of the housing and is disposed
on an edge of the light-transmitting sheet.
[0012] An embodiment provides a lighting device having a structure
in which the light-transmitting sheet can be coupled to a recess of
the housing in a sliding manner.
Technical Solution
[0013] According to an embodiment, a lighting device includes: a
housing having a first back cover and a second back cover on both
sides in a first axial direction; a first recess in which a lower
portion of the first back cover is opened; a second recess in which
a lower portion of the second back cover is opened; a heat radiator
disposed between the first and second recesses in a second axial
direction perpendicular to the first axial direction at a lower
portion of the housing; a first light-emitting module having a
plurality of light emitting diodes (LEDs) in a first region of the
heat radiator corresponding to the first recess; a second
light-emitting module having a plurality of LEDs in a second region
of the heat radiator corresponding to the second recess; a first
light-transmitting sheet disposed at the first recess so as to be
inclined with respect to the first axial direction and configured
to diffuse light emitted from the first light-emitting module; a
second light-transmitting sheet disposed at the second recess so as
to be inclined with respect to the first axial direction and
configured to diffuse light emitted from the second light-emitting
module; and a front cover configured to support a lower portion of
the heat radiator and lower end portions of the first and second
light-transmitting sheets, wherein the front cover includes a
fixing frame protruding to a direction of the heat radiator at the
lower portion of the heat radiator, and a cover plate extending to
a direction of the lower end portions of the first and second
light-transmitting sheets from the fixing frame.
[0014] According to an embodiment, a lighting device includes: a
housing having first and second back covers; first and second
recesses disposed on both sides of the housing in a first axial
direction and configured to have a parabolic shape in which a lower
portion of the first and second back covers is opened; a heat
radiator disposed between the first and second recesses in a second
axial direction; first and second light-emitting modules disposed
on opposite sides of the heat radiator and configured to have a
plurality of light emitting diodes (LEDs); a first
light-transmitting sheet disposed in the first recess of the
housing in a diagonal shape and configured to diffuse light emitted
from the first light-emitting module; a second light-transmitting
sheet disposed in the second recess of the housing in a diagonal
shape and configured to diffuse light emitted from the second
light-emitting module; a first reflective sheet attached to a
surface of a region adjacent to the LED in inner surfaces of the
first and second recesses and configured to reflect first side
light emitted from the plurality of LEDs; and a second reflective
sheet attached to a surface between the first reflective sheet and
upper end portions of the first and second light-transmitting
sheets in the inner surfaces of the first and second recesses,
wherein the heat radiator includes first and second reflective
portions extending to lower end portions of the first and second
light-transmitting sheets, and comprising a third reflective sheet
having a plurality of reflective surfaces having different radii of
curvature on the first and second reflective portions, wherein the
third reflective sheet includes an irregular reflective sheet.
[0015] According to an embodiment, a lighting device includes: a
housing having first and second back covers; first and second
recesses disposed on both sides of the housing in a first axial
direction and in which a lower portion of the first and second back
covers is opened; a heat radiator disposed between the first and
second recesses in a second axial direction; first and second
light-emitting modules disposed on opposite sides of the heat
radiator and configured to have a plurality of light emitting
diodes (LEDs); a first light-transmitting sheet disposed in the
first recess of the housing in a diagonal shape and configured to
diffuse light emitted from the first light-emitting module; a
second light-transmitting sheet disposed in the second recess of
the housing in a diagonal shape and configured to diffuse light
emitted from the second light-emitting module; and a front cover
coupled under the heat radiator and configured to support under
lower end portions of the first and second light-transmitting
sheets, wherein the front cover includes a fixing frame protruding
in a direction of the heat radiator, and a cover plate extending in
a direction of the lower end portions of the first and second
light-transmitting sheets below the fixing frame.
[0016] According to an embodiment, a lighting device includes: a
housing having first and second back covers; first and second
recesses disposed on both sides of the housing in a first axial
direction and in which a lower portion of the first and second back
covers is opened; a heat radiator disposed between the first and
second recesses in a second axial direction; first and second
light-emitting modules disposed on opposite sides of the heat
radiator and having a light emitting diode (LED); a first
light-transmitting sheet disposed in the first recess of the
housing in a diagonal shape and configured to diffuse light emitted
from the first light-emitting module; a second light-transmitting
sheet disposed in the second recess of the housing in a diagonal
shape and configured to diffuse light emitted from the second
light-emitting module; and a front cover coupled under the heat
radiator and configured to support under lower end portions of the
first and second light-transmitting sheets, wherein the housing
includes latching jaws disposed on both sidewalls of the first and
second recesses, wherein each of the latching jaws includes a first
supporting portion disposed on both sides in a second axial
direction of the first light-transmitting sheet, a second
supporting portion disposed on both sides in a second axial
direction of the second light-transmitting sheet, and a light
leakage-preventing portion protruding from the first and second
supporting portions in a direction of a lower surface of the
housing and facing one side of the first and second
light-transmitting sheets.
[0017] According to an embodiment, a lighting device includes: a
housing having first and second back covers; first and second
recesses disposed on both sides of the housing in a first axial
direction and in which a lower portion of the first and second back
covers are opened; a heat radiator disposed between the first and
second recesses in a second axial direction; first and second
light-emitting modules disposed on opposite sides of the heat
radiator and configured to have a plurality of light emitting
diodes (LEDs); a first light-transmitting sheet disposed in the
first recess of the housing in a diagonal shape and configured to
diffuse light emitted from the first light-emitting module; a
second light-transmitting sheet disposed in the second recess of
the housing in a diagonal shape and configured to diffuse light
emitted from the second light-emitting module; and a front cover
coupled under the heat radiator and configured to support under
lower end portions of the first and second light-transmitting
sheets, wherein the housing includes latching jaws disposed on both
sidewalls of the first and second recesses, and first and second
latching jaws disposed long in the second axial direction on upper
surfaces of the first and second recesses, wherein the first
light-transmitting sheet is disposed under a latching jaw of the
first recess and on the first latching protrusion, and the second
light-transmitting sheet is disposed under a latching jaw of the
second recess and on the second latching protrusion.
Advantageous Effects
[0018] An embodiment may provide a new lighting device for a flat
panel.
[0019] An embodiment may improve uniformity and glare of light in a
lighting device.
[0020] An embodiment may reflect side light of a plurality of light
emitting diodes (LEDs) to improve glare in a light-transmitting
sheet.
[0021] An embodiment may improve a light distribution in a narrow
gap between an upper surface of a recess in a back cover and an
oblique light-transmitting sheet.
[0022] In an embodiment, a front cover is detachably attached to a
lower center of a housing to cover a lower end portion of a heat
radiator and both side light-transmitting sheets, and thus an
appearance design can be changed into various forms.
[0023] An embodiment can improve leakage of light leaking through a
gap between an inner wall of a front cover and the front cover at
the lower center of the housing.
[0024] In an embodiment, a holder does not need to be provided by
combining a light-transmitting sheet in a sliding form in the
recess of the housing and an assembling process can be reduced.
[0025] In an embodiment, reliability of a lighting device can be
improved.
DESCRIPTION OF DRAWINGS
[0026] FIG. 1 is an exploded perspective view of a lighting device
according to an embodiment.
[0027] FIG. 2 is an assembled perspective view of a lighting device
of FIG. 1.
[0028] FIG. 3 is a side cross-sectional view of a lighting device
of FIG. 1.
[0029] FIG. 4 is a partially enlarged view of a lighting device of
FIG. 2.
[0030] FIG. 5 is an exploded perspective view of a heat radiator
and a front cover of FIG. 1.
[0031] FIG. 6 is a partially enlarged view of a heat radiator and a
front cover of FIG. 1.
[0032] FIG. 7 is an assembled perspective view of a heat radiator
and a front cover of FIG. 5.
[0033] FIG. 8 is an enlarged view of a first back cover of a
lighting device of FIG. 3 illustrating a comparison of each
reflection region in a first recess.
[0034] FIG. 9 is an enlarged view of a first back cover of a
lighting device of FIG. 3.
[0035] FIG. 10 is a view illustrating first and third reflective
sheets on a first back cover of FIG. 9.
[0036] FIG. 11 is a view illustrating an optical path by a third
reflective sheet in a first back cover of a lighting device of FIG.
9.
[0037] FIG. 12 is a partially enlarged view of FIG. 11 for
explaining a problem caused by a gap between a light-transmitting
sheet and a recess top surface.
[0038] FIG. 13 is a sectional view taken along line A-A of a
lighting device of FIG. 2.
[0039] FIG. 14 is a side cross-sectional view illustrating a
combination of a heat radiator and a front cover in a housing
according to an embodiment.
[0040] FIG. 15 to 17 are views illustrating another example of a
front cover according to an embodiment.
[0041] FIG. 18 is a view illustrating a latching jaw disposed on an
inner sidewall of a housing of FIG. 1.
[0042] FIG. 19 is a perspective view of a housing of FIG. 1 before
a front cover is coupled.
[0043] FIG. 20 is a view illustrating a latching jaw and a
light-transmitting sheet in an inner sidewall of a housing in FIG.
19.
[0044] FIG. 21 is a view illustrating a front cover and a
light-transmitting sheet on a latching jaw of a housing in FIG.
19.
[0045] FIG. 22 is a partially enlarged view of FIG. 21.
[0046] FIG. 23 is a view illustrating an example in which a
light-transmitting sheet and a front cover are coupled on a
latching jaw in FIG. 19.
[0047] FIG. 24 is a view illustrating a latching jaw of a housing,
a light-transmitting sheet and a front cover in FIG. 23.
[0048] FIG. 25 is a view illustrating an example in which both end
portions of a light-transmitting sheet are combined in FIG. 19.
[0049] FIG. 26 is a partially enlarged view of FIG. 25.
[0050] FIG. 27 is a side cross-sectional view illustrating a light
emitting diode (LED) according to an embodiment.
MODES OF THE INVENTION
[0051] Hereinafter, preferred embodiments of a lighting device
according to an embodiment will be described with reference to the
accompanying drawings. Terms described below are terms defined in
consideration of functions in the present embodiments and may vary
depending on the intention of a user or operator or a practice.
Therefore, such terms should be defined on the basis of the entire
contents disclosed herein. In addition, the following embodiments
are not intended to limit the scope of the present invention, but
are merely presented as examples, and there may be various
embodiments implemented through the technical idea.
[0052] Hereinafter, a preferred embodiment of the present invention
will be described in more detail with reference to the accompanying
drawings. Meanwhile, term "lighting module or lighting device" as
used herein refers to a lighting device used for indoors or
outdoors, and it is clearly put in advance that it is used as a
collective term of similar apparatuses such as flat panel lamps,
light fixtures, street lights, various lamps, electronic bulletin
boards, headlights, etc.
[0053] FIG. 1 is an exploded perspective view of a lighting device
according to an embodiment. FIG. 2 is an assembled perspective view
of a lighting device of FIG. 1, FIG. 3 is a side cross-sectional
view of a lighting device of FIG. 1, FIG. 4 is a partially enlarged
view of a lighting device of FIG. 2, FIG. 5 is an exploded
perspective view of a heat radiator and a front cover of FIG. 1,
FIG. 6 is a partially enlarged view of a heat radiator and a front
cover of FIG. 1, and FIG. 7 is an assembled perspective view of a
heat radiator and a front cover of FIG. 5.
[0054] Referring to FIGS. 1 to 7, a lighting device 100 includes a
housing 110 having back covers 111 and 112 having recesses 115 and
115A whose lower portion is opened, a heat radiator 150 disposed at
a lower portion of a center of the back covers 111 and 112,
light-emitting modules 170 and 170A disposed on the heat radiator
150, and light-transmitting sheets 180 and 182 disposed on the
recesses 115 and 115A of the back covers 111 and 112.
[0055] Referring to FIGS. 1 to 3, the housing 110 includes back
covers 111 and 112 having recesses 115 and 115A whose lower portion
is convexly upwardly recessed. The back covers 111 and 112 may
include the first and second back covers 111 and 112 symmetrical
with respect to a center line in a second Z-axis direction. The
recesses 115 and 115A may have a symmetrical shape to each other
with respect to a center line in a second Z-axis direction at a
lower portion of a center side of the housing 110. The second
Z-axis direction may be a central axis direction. The back covers
111 and 112 and the recesses 115 and 115A may be disposed in a
shape symmetrical in a first X-axis direction with respect to a
center line in a second axis direction. The first X-axis direction
may be perpendicular to the second Y-axis direction on the same
horizontal plane. A direction orthogonal to the first X-axis
direction and the second Z-axis direction may be a height direction
or a thickness direction and a third Y-axis direction.
[0056] The recesses 115 and 115A may include first and second
recesses 115 and 115A disposed on both sides in the first axis
direction with respect to the second Z-axis direction of a center
side of the housing 110. A lower portion of the first back cover
111 may be opened at the first recess 115, and a lower portion of
the second back cover 112 may be opened at the second recess 115A.
The first back cover 111 may have the first recess 115 at the lower
portion thereof, and the second back cover 112 may have the second
recess 115A at the lower portion thereof. The first and second
recesses 115 and 115A are convex upward on an X-Z plane, and the
first and second back covers 111 and 112 may be disposed on an
outer periphery of the first and second recesses 115 and 115A.
[0057] Inner surfaces of the first and second back covers 111 and
112 may include recesses 115 and 115A having a parabola shape or an
ellipse shape. The outer shape of the first and second back covers
111 and 112 may include a plurality of parabolic shapes, a
plurality of ellipse shapes, a hyperbola, or a pair of curved
surfaces, and is not limited thereto. A heat-dissipating member,
for example, the heat radiator 150 may be disposed in a region
between the first and second recesses 115 and 115A. The first and
second back covers 111 and 112 may be in a line-symmetrical shape
with respect to the second Z-axis direction of a center side. A
power supply device (not shown) may be provided on the back covers
111 and 112, and is not limited thereto.
[0058] The housing 110 may have both sidewalls of the recesses 115
and 115A, and the both sidewalls may be disposed facing each other
with respect to the second Z-axis direction. A reflective material
or a reflective sheet (not shown) may be further disposed on inner
surfaces of the both sidewalls of the recesses 115 and 115A for
reflection of light, but is not limited thereto. A depth of the
recesses 115 and 115A may be formed deeper toward a center region
of the back covers 111 and 112. The first and second recesses 115
and 115A may be different lighting regions.
[0059] Referring to FIGS. 2 and 3, when viewed in the X-Z plane, a
length X1 in the first X-axis direction and a length Z1 in the
second Z-axis direction may be the same or different from each
other in the housing 110. The length X1 may have a relationship of
X1.gtoreq.Z1 or may have a relationship of X1.ltoreq.Z1. When the
length X1 differs from the length Z1, the difference may be 5 times
or less.
[0060] A thickness Y1 or a height of the housing 110 may be 1/10 or
less of a length in the first X-axis direction and/or the second
Z-axis direction, and for example, may range from 49 to 59 mm. The
thickness Y1 of the housing 110 may be disposed to be 1/10 or less
of a length in the first X-axis direction and/or the second Z-axis
direction so that a lighting device having a slim thickness can be
provided. The first X-axis direction is a transverse direction or a
width direction of the housing 110 and the second Z-axis direction
is an axial direction orthogonal to the first X-axis direction. The
third Y-axis direction may be a height or a thickness direction.
Here, a size X1.times.Z1 of the lighting device is 550 to 600
mm.times.550 to 600 mm, and a thickness or height Y1 may be in a
range of 50 to 52 mm, and is not limited thereto.
[0061] A receiving protrusion 113 may be disposed at both edges 114
of the housing 110 and the receiving protrusion 113 may be coupled
to another structure such as a ceiling. The receiving protrusion
113 may have a stepped structure or a latching jaw structure with
respect to the edge 114, or may have a protruding structure that
further protrudes in an outward direction. As shown in FIG. 3, a
plurality of fastening holes 105 may be disposed in the first and
second back covers 111 and 112 of the housing 110 to be fastened to
other structure.
[0062] As shown in FIGS. 1 and 3, a connection portion 117 may be
disposed in a region between the first and second back covers 111
and 112. The connection portion 117 may be disposed in a region
between an outer curved surface of the first back cover 111 and an
outer curved surface of the second back cover 112. An upper surface
of the connection portion 117 may be disposed lower than outer
surfaces of the first and second back covers 111 and 112. The
connection portion 117 may be formed in the second Z-axis direction
or a central axis direction of the housing 110. One or a plurality
of fastening protrusions 90 may protrude from the connection
portion 117 and the fastening protrusions 90 may be a component
such as a boss or a fastening part such as a screw or a rivet. The
connection portion 117 may be provided with a fastening hole into
which a fastening part such as a screw is inserted, but is not
limited thereto. Since the fastening protrusions 90 are coupled
through the heat radiator 150, a flow of the heat radiator 150 may
be suppressed. The upper surface of the connection portion 117 may
be a plane, for example, a horizontal plane. When the upper surface
of the connection portion 117 is a plane, a contact area with other
structure may be increased or a structure such as a power supply
device may be easily adhered or fixed. A thickness of the
connection portion 117 may be formed greater than that of the first
and second back covers 111 and 112. The thickness of the first and
second back covers 111 and 112 is a distance between an upper
surface of the recesses 115 and 115A and an outer curved surface of
the back covers 111 and 112. The connection portion 117 may support
the heat radiator 140 and may be coupled to a power supply
device.
[0063] The housing 110, for example, the back covers 111 and 112
may include a plastic material, and for example, may include at
least one of polycarbonate (PC), polyethylene terephthalate glycol
(PETG), polyethylene (PE), polystyrene paper (PSP), polypropylene
(PP), and polyvinyl chloride (PVC).
[0064] The back covers 111 and 112 may have a material having
higher reflectance than transmittance and may be a material having
reflectance of 70% or more, for example, 80% or more. Light
incident on surfaces of the back covers 111 and 112 may be
reflected by increasing the reflectance of the back covers 111 and
112. The back covers 111 and 112 may be a material having light
absorption rate of 20% or less, for example, 15% or less, but is
not limited thereto. The back covers 111 and 112 may be added with
a metal oxide in a resin material such as silicone or epoxy. The
back covers 111 and 112 are formed of a white resin material,
thereby improving a reflection efficiency of light.
[0065] The heat radiator 150 may be disposed in the second Z-axis
direction under the third Y-axis direction of the housing 110. The
heat radiator 150 may be disposed on the opposite region of the
connection portion 117 of the housing 110. The heat radiator 150
may be disposed in the Z-axis direction in a region between the
first and second recesses 115 and 115A. The heat radiator 150 may
be disposed in a region overlapping with the connection portion 117
of the housing 110 in the Y-axis direction. The heat radiator 115
may be disposed above a horizontal plane of a lower surface of the
housing 110 or may be disposed in a non-protruding structure. The
heat radiator 150 may be in a bar shape.
[0066] The heat radiator 150 may be made of a metal material, and
for example, may include at least one of metals such as aluminum,
copper, nickel, and silver, and is not limited thereto. The heat
radiator 150 may include a carbon material, and is not limited
thereto.
[0067] Referring to FIGS. 3 to 6, the heat radiator 150 includes
heat dissipation parts 151 and 151A disposed on opposite sides of
each other with respect to the third Y-axis direction and
reflectors 153 and 153A protruding in opposite directions to each
other at a lower portion of the heat dissipation parts 151 and
151A.
[0068] The heat dissipation parts 151 and 151A may have a vertical
surface in the recesses 115 and 115A direction, and the vertical
surface may include a flat surface. The vertical surface may
correspond to each of the light-transmitting sheets 180 and 182.
The heat dissipation parts 151 and 151A may include a first heat
dissipation part 151 disposed on an inner side of the first recess
115 and a second heat dissipation part 151A disposed on an inner
side of the second recess 115A. The first heat dissipation part 151
and the second heat dissipation part 151A may be disposed in
opposite directions to each other with respect to the heat radiator
150. The first heat dissipation part 151 may have a vertical
surface in the Y-axis direction in the inner side of the first
recess 115 and the second heat dissipation part 151A may have a
vertical surface in the Y-axis direction in the inner side of the
second recess 115A. The vertical surfaces of the first and second
heat dissipation parts 151 and 151A may be flat surfaces and
disposed at a right angle to the first X-axis direction in the
third Y-axis direction or a thickness direction.
[0069] The heat radiator 150 may have a heat-dissipating hole 159
and the heat-dissipating hole 159 may be disposed in the second
Z-axis direction. The heat-dissipating hole 159 may be disposed in
the same axial direction as an axial direction in which a light
emitting diode (LED) 173 is disposed. A side cross-section of the
heat-dissipating hole 159 may be in a polygonal or circular shape,
but is not limited thereto. The heat-dissipating hole 159 may be
provided with an open structure at both end portions as shown in
FIG. 6. Such a heat-dissipating hole 159 may provide a vertical or
horizontal direction path through which heat conducted from the
first and second heat dissipation parts 151 and 151A may be
transferred. The heat radiator 150 may include an upper frame 159A
disposed above the heat-dissipating hole 159 and a lower frame 159B
disposed below the heat-dissipating hole 159. The upper frame 159A
and the lower frame 159B may be bent or coupled from the first and
second heat dissipation parts 151 and 151A.
[0070] The heat-dissipating hole 159 may be disposed in a region
between the first and second heat dissipation parts 151 and 151A
and the upper and lower frames 159A and 159B. A plurality of
insertion holes 91 penetrate in the Y-axis direction in the upper
frame 159A and the lower frame 159B, and the fastening protrusion
90 in FIG. 1 of the housing 110 may be inserted thereto. A
fastening hole 92 may be disposed along a fixing frame 157 as shown
in FIG. 6 in a front cover 155 corresponding to the insertion hole
91. Accordingly, a fastening part 19 on the housing 110 of FIG. 1
may be used to fasten to the fastening hole 92 of the front cover
155 via the fastening protrusion 90.
[0071] The light-emitting modules 170 and 170A may be disposed on
the heat radiator 150 in the Z-axis direction. The light-emitting
modules 170 and 170A may be coupled to opposite sides of the heat
radiator 150 in the X-axis direction. The light-emitting modules
170 and 170A may have a long length in a longitudinal direction of
the heat radiator 150. The light-emitting modules 170 and 170A emit
light in the different directions of recesses 115 and 115A.
[0072] The light-emitting modules 170 and 170A may be disposed on
vertical surfaces of the heat dissipation parts 151 and 151A of the
heat radiator 150. The light-emitting modules 170 and 170A include
a plurality of light-emitting modules and for example, may include
first and second light-emitting modules 170 and 170A. The first
light-emitting module 170 is disposed in a first region of the heat
radiator 150 corresponding to the first recess 115, and the second
light-emitting module 170A may be disposed in a second region of
the heat radiator 150 corresponding to the second recess 115A. The
first light-emitting module 170 emits light through the first
recess 115 and the second light-emitting module 170A emits light
through the second recess 115A. The first light-emitting module 170
may be disposed in the first heat dissipation part 151 and the
second light-emitting module 170A may be disposed in the second
heat dissipation part 151A.
[0073] Some light in light emitted from the first and second
light-emitting modules 170 and 170A may be reflected and some light
may be irradiated to the light-transmitting sheets 180 and 182.
When light emitted in a horizontal direction from the first and
second light-emitting modules 170 and 170A is irradiated to the
light-transmitting sheets 180 and 182, this may be defined as
direct lighting. When the reflected light is irradiated to the
light-transmitting sheets 180 and 182, it can be defined as
indirect lighting. The light-transmitting sheets 180 and 182 may be
disposed in one or more than one. The light-transmitting sheets 180
and 182 may include a first light-transmitting sheet 180 disposed
on the first recess 115 and a second light-transmitting sheet 182
disposed on the second recess 115A.
[0074] As shown in FIG. 4, the reflectors 153 and 153A may have a
predetermined curvature from the heat dissipation parts 151 and
151A on opposite sides respectively, and extend in opposite
directions to each other. The reflectors 153 and 153A may be
disposed at a lower portion of the heat dissipation parts 151 and
151A. The reflectors 153 and 153A may extend integrally from the
heat dissipation parts 151 and 151A. The reflectors 153 and 153A
may include a plurality of reflection regions having surfaces
having different radii of curvature and reflecting incident light.
The reflectors 153 and 153A include first and second reflectors 153
and 153A extending from each of the heat dissipation parts 151 and
151A.
[0075] The front cover 155 is disposed at a lower portion of the
heat radiator 150. The front cover 155 may be coupled to the lower
portion of the heat radiator 150. The front cover 155 may overlap
the heat radiator 150 in the Y-axis direction and may be disposed
along the heat radiator 150 in the Z-axis direction. The front
cover 155 may prevent a lower region of the heat radiator 150 from
being exposed. A width of the front cover 155 in the X-axis
direction may be larger than a gap between the first and second
light-emitting modules 170 and 170A. A width of the front cover 155
in the horizontal direction may be wider than that of the
connection portion 117 in the X-axis direction. Such a front cover
155 may cover a lower region between the recesses 115 and 115A.
[0076] The first reflector 153 is disposed between the first heat
dissipation part 151 and the front cover 155 and the second
reflector 153A is disposed between the second heat dissipation part
151A and the front cover 155. The front cover 155 may be disposed
at a lower portion of the first reflector 153 and the second
reflector 153A to prevent lower surfaces of the first and second
reflectors 153 and 153A from being exposed to an outside. Each edge
of the first and second reflectors 153 and 153A may be disposed on
a region corresponding to both edges of the front cover 155.
[0077] The first and second reflectors 153 and 153A may have a
curved shape. Inner surfaces of the first and second reflectors 153
and 153A may have a curved surface. The first reflector 153 may
extend from the first heat dissipation part 151 to the outside of a
lower end portion of the first light-transmitting sheet 180. The
second reflector 153A may extend from the second heat dissipation
part 151A to the outside of a lower end portion of the second
light-transmitting sheet 182. An inner surface of the first
reflector 153 may include a reflection region having different
radii of curvature and an inner surface of the second reflector
153A may include a reflection region having different radii of
curvature. The inner surfaces of the first and second reflectors
153 and 153A may be disposed in directions of the first and second
recesses 115 and 115A.
[0078] An upper end portion of the first reflector 153 may be
disposed at a lower portion of the first light-emitting module 170
and an upper end portion of the second reflector 153A may be
disposed at a lower portion of the second light-emitting module
170A. The first and second reflectors 153 and 153A are adjacent to
the lower portions of the first and second light-emitting modules
170 and 170A and reflect side light transferring downward from
light emitted from the LED 173. The reflected light may transfer to
inner surfaces of the light-transmitting sheets 180 and 182 and the
back covers 111 and 112. A third reflective sheet 162 may be
disposed on the inner surfaces of the reflectors 153 and 153A, or
the inner surfaces may be coated with a reflective material, or a
metal surface of the heat radiator 150 may be exposed. The upper
end portions of the reflectors 153 and 153A may overlap the LED 173
of the light-emitting modules 170 and 170A in a vertical direction,
thereby effectively reflecting incident light.
[0079] Referring to FIGS. 4, 6 and 7, the heat radiator 150 may
include reflection frames 154 and 154A on an outer side of an upper
portion thereof, and the reflection frames 154 and 154A may
protrude in an outward direction further than the upper frame 159A.
The reflection frames 154 and 154A may be bent in an outward
direction from upper portions of the first and second heat
dissipation parts 151 and 151A, for example, in the first and
second recess directions. The reflection frames 154 and 154A may
overlap with the light-emitting modules 170 and 170A in a vertical
direction and may reflect light emitted in an upward direction from
the LED 173. The reflection frames 154 and 154A may cover upper
regions of the first and second light-emitting modules 170 and
170A. The reflection frames 154 and 154A may be in close contact
with or bonded to a lower surface of the center side connection
portion 117 of the housing 110. A concave groove 117A may be
provided on the lower surface of the center side connection portion
117 so that the reflection frames 154 and 154A may be inserted into
the groove 117A. An upper surface and outer surface of the
reflection frame 117A may be in contact with the groove 117A.
[0080] Referring to FIGS. 4 to 7, the front cover 155 may be
disposed under the heat radiator 150. The front cover 155 may
include a metal material or a non-metal material, and may be
coupled to the heat radiator 150. When the front cover 155 is a
metal material, heat conducted from the heat radiator 150 may be
dissipated to an outside. When the heat radiator 150 is a
non-metallic material, for example, a plastic material, a design of
the front cover 155 may be changed variously.
[0081] The front cover 155 may include a fixing frame 157 disposed
below the lower frame 159B of the heat radiator 150 and a cover
plate 156 disposed below the fixing frame 157.
[0082] The fixing frame 157 of the front cover 155 may have a
plurality of fastening holes 92 and be inserted into a receiving
groove 153B of the lower frame 159B of the heat radiator 150, and
the fastening member 19 in FIG. 1 fastened via the heat radiator
150 may be fastened to the fastening hole 92. Accordingly, the
front cover 155 may be fixed to the heat radiator 150, and the heat
radiator 150 may be fixed to the housing 110. The cover plate 156
of the front cover 155 may extend into regions of the first and
second recesses 115 and 115A. The cover plate 156 may be formed as
a curved surface or an inclined surface on an upper surface or a
lower surface thereof. The cover plate 156 may be formed in a
symmetrical shape with respect to a center line in the second
Z-axis direction.
[0083] As shown in FIGS. 4 and 6, the heat radiator 150 may include
a light leakage-preventing protrusion 62 protruding from an end
portion 61 of the first and second reflectors 153 and 153A in the
front cover direction or a downward direction. The end portion 61
of the first and second reflectors 153 and 153A and the cover plate
156 of the front cover 155 are spaced apart from each other, a
region between the end portion 61 of the first and second
reflectors 153 and 153A and the cover plate 156 may be provided
with a latching groove 158, and the lower end portions of the
light-transmitting sheets 180 and 182 may be disposed in the
latching groove 158, respectively. The light leakage-preventing
protrusion 62 may be disposed to face one sides of the
light-transmitting sheets 180 and 182, respectively.
[0084] As shown in FIGS. 1, 4 and 7, each of the light-emitting
modules 170 and 170A includes a circuit board 171 and a plurality
of LEDs 173 disposed on the circuit board 171. The circuit board
171 may be upright in the third Y-axis direction and have a long
length in the second Z-axis direction. The plurality of LEDs 173
may be disposed in a longitudinal direction of the circuit board
171 or in the second Z-axis direction. The first and second
light-emitting modules 170 and 170A may be disposed in opposite
directions to each other in a region between the first and second
recesses 115 and 115A.
[0085] The circuit board 171 may be disposed long on the heat
dissipation parts 151 and 151A in a longitudinal direction (Z-axis
direction) of the heat radiator 150. The circuit board 171 may be
disposed in one or plural on the heat dissipation parts 151 and
151A, and is not limited thereto. The circuit board 171 may be
arranged in one or plural on each of the heat dissipation parts 151
and 151A. The circuit board 171 may be fastened with a screw and/or
bonded with adhesive on the heat dissipation parts 151 and 151A,
and is not limited thereto. The circuit board 171 may include, for
example, a printed circuit board (PCB). The PCB includes at least
one of a resin material PCB, a metal core PCB (MCPCB), and a
flexible PCB (FPCB), and for example, may be provided as a metal
core PCB for heat dissipation.
[0086] The LED 173 may emit at least one of blue, red, green,
white, and UV light as a package in which a light emitting chip is
packaged, and for example, white light may be emitted for lighting.
The LED 173 may be mounted on the circuit board 171 in a chip form,
and in this case, a directional angle of the LED 173 may be 115
degrees or more, for example, 118 degrees or more, and is not
limited thereto. Such a directional angle of the LED 173 may vary
depending on a structure of a package or a shape of a cavity in a
package, and is not limited thereto. The LED 173 may be disposed on
the circuit board 171 in one row or two or more rows, and is not
limited thereto.
[0087] The LED 173 according to an embodiment may include, for
example, a warm white LED and a cool white LED on each circuit
board 171. The warm white LED and the cool white LED are elements
that emit white light. Since the warm white LED and the cool white
LED may emit the white light of mixed light by radiating a
correlated color temperature, the color rendering index (CRI),
which is close to natural sunlight becomes high. Accordingly, it is
possible to prevent a color of an actual object from being
distorted, thereby reducing fatigue of a user's eyes.
[0088] As shown in FIG. 3, the first light-transmitting sheet 180
may be disposed on the first recess 115 and the second
light-transmitting sheet 182 may be disposed on the second recess
115A. The first light-transmitting sheet 180 may be inclined with
respect to the X-axis direction. The second light-transmitting
sheet 182 may be inclined with respect to the X-axis direction. The
first and second light-transmitting sheets 180 and 182 may have the
same angle in the X-axis direction with respect to a center between
the first and second recesses 115 and 115A. The first
light-transmitting sheet 180 may be disposed above the horizontal
X-Z plane of a bottom of the first recess 115. The second
light-transmitting sheet 182 may be disposed above the horizontal
X-Z plane of a bottom of the first recess 115A.
[0089] Upper end portions of the first and second
light-transmitting sheets 180 and 182 may be disposed higher than
lower end portions thereof. The lower end portions of the first and
second light-transmitting sheets 180 and 182 may be disposed closer
to the heat radiator 150 than the upper end portions. The first and
second light-transmitting sheets 180 and 182 may have a gradually
higher height as they become farther from the heat radiator
150.
[0090] The first recess 115 has a first protrusion 125 on an inner
side, and the first protrusion 125 may protrude in an inward
direction of the first recess 115 or in the direction of the heat
radiator 150. The first protrusion 125 may be formed to be long in
the Z-axis direction. The first and second protrusions 125 may have
a first groove 118 at an upper portion thereof. The second recess
115A has a second protrusion 125A on an inner side, and the second
protrusion 125A may protrude in an inward direction of the second
recess 115A or in the direction of the heat radiator 150. The
second protrusion 125A may be formed to be long in the Z-axis
direction.
[0091] The first and second protrusions 125 and 125A may be
disposed at a predetermined position on inner surfaces of the first
and second recesses 115 and 115A, and for example, may be disposed
at an outer side of a center of the first and second recesses 115
and 115A. The first and second protrusions 125 and 125A protrude
from upper surfaces of the back covers 111 and 112 in the
directions of the first and second recesses 115 and 115A. The first
and second protrusions 125 and 125A may be disposed along the
second Z-axis direction in a center of the upper surface of the
first and second recesses 115. The first and second protrusions 125
and 125A may be disposed in outer peripheries of the upper end
portions of the first and second light-transmitting sheets 180 and
182. The first and second protrusions 125 and 125A may have the
same material as or a different material from that of the first and
second back covers 111 and 112, and are not limited thereto.
[0092] The upper end portion of the first light-transmitting sheet
180 may be placed on the first protrusion 125 of the first recess
115. The upper end portion of the first light-transmitting sheet
180 may be inserted into the first groove 118. The lower end
portion of the first light-transmitting sheet 180 may be disposed
in the second groove 158 between the first reflector 153 of the
heat radiator 150 and the front cover 155. The second groove 158
may be formed by the first reflector 153 of the heat radiator 150
and the front cover 155. The upper end portion of the second
light-transmitting sheet 180A may be placed on the second
protrusion 125A of the second recess 115A. The upper end portion of
the second light-transmitting sheet 180A is disposed in the first
groove 118 and the lower end portion thereof may be disposed in the
second groove 158 between the second reflector 153A of the heat
radiator 150 and the front cover 155. The second groove 158 may be
formed by the second reflector 153A of the heat radiator 150 and
the front cover 155.
[0093] The light-transmitting sheets 180 and 182 may be a sheet
having a diffusing agent or may include a diffusion sheet material.
The light-transmitting sheets 180 and 182 may include a diffusion
sheet, for example, at least one of polymethyl methacrylate (PMMA),
polypropylene (PP), polyethylene (PE), and polystyrene (PS).
[0094] The light-transmitting sheets 180 and 182 may include a
plurality of layers, for example, a diffusion film and a diffusion
plate on the diffusion film. The diffusion film may include at
least one of polyethylene terephthalate (PET), PS, and PC, and the
diffusion plate may include at least one of PC, PS, and PMMA. The
diffusion film diffuses incident light, and the diffusion plate has
a thickness larger than a thickness of the diffusion film, diffuses
light passing through the diffusion film, and prevents from sagging
down.
[0095] Since the first recess 115 of the first back cover 111 is
disposed in the same structure as the second recess, hereinafter, a
structure of the second recess will be omitted, and the first
recess will be described. The second recess and the second
light-transmitting sheet will be described with reference to the
description of the first recess and the first light-transmitting
sheet.
[0096] Referring to FIGS. 8 and 9, the first light-transmitting
sheet 180 may be disposed in an oblique direction with respect to
an optical axis X0. The optical axis X0 may be an axial direction
perpendicular to an emitting surface of the LED 174. The optical
axis X0 may be parallel to the first X-axis direction.
[0097] Here, the upper end portion of the first light-transmitting
sheet 180 may be disposed on the first protrusion 125 and the lower
end portion thereof may be disposed on the cover plate 156 of the
front cover 155. The front cover 155 or the cover plate 156 may be
disposed at a position lower than the first protrusion 125.
[0098] The first light-transmitting sheet 180 may be inclined at a
predetermined angle .theta.1 with respect to the X-axis direction
of the housing 110. The light-transmitting sheet 180 may be
disposed in a shape inclined with respect to the optical axis X0 in
the first recess 115 of the first back cover 111. The inclined
angle .theta.1 of the first light-transmitting sheet 180 may be 45
degrees or less with respect to the X-axis direction of the housing
110. The angle .theta.1 may be inclined in a range of 9 to 13
degrees, for example, in a range of 11 to 12 degrees with respect
to the optical axis X0. When the inclined angle .theta.1 of the
first light-transmitting sheet 180 is out of the above range, a
distribution of light reflected in the recess 115 may not be
uniform and an uniform luminance distribution may not be provided
by the light directly incident on the first light-transmitting
sheet 180. By being inclined at the angle .theta.1, such a
light-transmitting sheet 180 may correspond to the LED 173 in the
horizontal direction. The first light-transmitting sheet 180 may
receive and diffuse light reflected via a surface of the first
recess 115 so as to irradiate the light.
[0099] The light emitting surface of the LED 173 or a back surface
of the circuit board 171 may be disposed at a right angle or in a
range of 89 to 91 degrees with respect to the first X-axis.
Accordingly, light emitted from the LED 173 may be directly
irradiated onto entire regions B1, B2, and B3 of the first
light-transmitting sheet 180. The first light-transmitting sheet
180 may directly receive and diffuse light emitted from the LED 173
by the inclined angle .theta.1. As another example, when the LED
173 is out of the angle with respect to the first X-axis, light
emitted from the LED 173 may not be irradiated to a partial region
of the first light-transmitting sheet 180, and the reflected light
may be used.
[0100] Referring to FIGS. 8 to 10, in the first recess 115,
reflective regions M1, M2, and M3 for changing a path of light
emitted from the LED 173 may be disposed, or reflective sheets 160
and 165 may be attached on at least one of the reflective regions
M1, M2 and M3.
[0101] The inner surface of the back cover 111 may have a plurality
of reflective regions M1 and M2 disposed between the LED 173 and
the upper end portion of the light-transmitting sheet 180. The
reflective regions M1 and M2 may include a first reflective region
M1 adjacent to the LED 173 and a second reflective region M2
disposed between the first reflective region M1 and the upper end
portion of the light-transmitting sheet 180.
[0102] The first reflective region M1 may be a section from a
highest point of the first recess 115 to a point adjacent to the
LED 173 on an inner side surface of the first recess 115. The
second reflective region M2 may be a section from the highest point
of the first recess 115 to a point adjacent to the upper end
portion of the light-transmitting sheet 180 on the inner side
surface of the first recess 115. That is, a boundary between the
first and second reflective regions M1 and M2 may be a highest
point portion of the first recess 115, and is not limited
thereto.
[0103] The first reflective region M1 may reflect first side light
L1 from light emitted from the LED 173 to the second reflective
region M2. The second reflective region M2 may reflect light
emitted from the LED 173 and light reflected from the first
reflective region M1 to the light-transmitting sheet 180. The first
reflective region M1 may include a plurality of reflective surfaces
or inclined surfaces having different radii of curvature. The
second reflective region M2 may include a plurality of reflective
surfaces or planes having different radii of curvature.
[0104] Referring to FIGS. 8 and 9, the first reflective region M1
is a regular reflection region and the second reflective region M2
is an irregular reflection region for incident light L1, L2, and
L3. The first and second reflective regions M and M2 may be
disposed above the optical axis X0. In addition, the latching
protrusion 125 may be spaced apart from the optical axis X0 by a
predetermined distance d1.
[0105] The first and second reflective regions M1 and M2 may be
disposed in a directional angle region with respect to the optical
axis X0 of the LED 173. Both ends of the first reflective region M1
may form an angle R3 ranging from 28 to 33 degrees with the LED 173
as a starting point P. When the angle R3 between both ends of the
first reflective region M1 and the starting point P of the LED 173
is larger than the above range, light that is regularly reflected
from the first reflective region M1 may be irradiated to the
light-transmitting sheet 180 to generate a bright line on the
light-transmitting sheet 180. When the angle R3 is smaller than the
above range, light that is regularly reflected from the first
reflective region M1 is not uniformly irradiated to the second
reflective region M2, and thus a light distribution is not uniform.
The first reflective region M1 may be disposed in an angle range
that allows the right side light L1 incident thereon to be
regularly reflected to different regions of the second reflective
region M2. Here, the starting point P may be a center of an
emitting surface of the LED 173.
[0106] The angle R3 may be wider than an angle R4 formed by both
ends of the second reflective region M2 with the LED 173 as a
starting point P. Both ends of the second reflective region M2 may
form an angle ranging from 21 to 26 degrees with respect to the LED
173 as a starting point P, and the angle may be smaller than the
angle R3 formed by the first reflective region M1. As both ends of
the second reflective region M2 are disposed at the angle R4 at a
center of an emitting surface of the LED 173 as a starting point P,
light reflected via the first reflective region M1, light reflected
via the third reflective region M3, and light emitted from the LED
173 may be irregularly reflected to be irradiated an entire region
of the light-transmitting sheet 180. When the second reflective
region M2 is larger than the angle R4, luminous intensity may be
lowered, and when the second reflective region M2 is smaller than
the angle R4, light uniformity may be lowered.
[0107] A starting point P of the LED 173 is a center of an emitting
surface and a straight line perpendicular to the emitting surface
may be defined as the optical axis X0. The light-transmitting sheet
180 may have a first point Px intersecting with the optical axis
X0, and the first point Px may be a point of 1/2 or more from an
upper end of the light-transmitting sheet 180, for example, may be
a point of 2/3. In addition, a second point Py may be a point of
1/3 from the upper end of the light-transmitting sheet 180.
[0108] The upper end of the light-transmitting sheet 180 and the
first point Px may have an angle R1 less than 10 degrees from the
LED 173 as a starting point P, and is not limited thereto. When the
angle R1 is 10 degrees or more, a bright line may be generated by
light directly incident on the light-transmitting sheet 180. The
angle R1 may vary depending on a tilting angle of the
light-transmitting sheet 180, and is not limited thereto.
[0109] As a starting point P of the LED 173, an angle R1+R2 formed
by both ends of the light-transmitting sheet 180 may be greater
than the angle R3 or R4 formed by the first reflective region M or
the second reflective region M2, for example, in a range of 34 to
39 degrees. When the angle R1+R2 formed by both ends of the
light-transmitting sheet 180 is smaller than the above range, a
diffusion effect of light may be reduced and a light uniformity may
be reduced, and when the angle R1+R2 formed by both ends of the
light-transmitting sheet 180 is larger than the above range, a
generation of the bright line may be increased by light incident
directly.
[0110] The reflector 153 may be a third reflective region M3 and
the third reflective region M3 may reflect incident light to the
second reflective region M2 and/or the light-transmitting sheet
180. As a starting point P of the LED 173, an angle R5 formed by
both ends of the lower third reflective region M3 may be greater
than the angle R3 or R5 formed by the first reflective region M1 or
the second reflective region M1. The third reflective region M3 may
be a regular reflection region or an irregular reflection region.
The third reflective region M3 may reflect incident light to the
second reflective region M2 and the light-transmitting sheet 180 to
suppress a generation of a bright line in the light-transmitting
sheet 180. A region of the third reflective region M3 adjacent to
the LED 173 may cover a region of the LED 173, which is out of a
directional angle, thereby reducing light leakage.
[0111] At least one of the reflective regions M1, M2, and M3 may
include a reflective sheet. For example, as shown in FIGS. 9 and
10, reflective sheets 160, 165 and 162 may be disposed on the inner
surface of the back cover 111 and on the reflector 153. The
reflective sheets 160, 165, and 162 may include first to third
reflective sheets 160, 165, and 162 disposed in different
regions.
[0112] The first reflective sheet 160 may be disposed in the first
reflective region M1 and the second reflective sheet 165 may be
disposed in the second reflective region M2. The third reflective
sheet 162 may be disposed in the third reflective region M3. The
first reflective sheet 160 may be attached to a surface of a region
adjacent to the LED 173 from a highest point of the recess 115 in
inner surfaces of each recesses 115. The second reflective sheet
165 may be attached to a region adjacent to the upper end portion
of the light-transmitting sheet 180 from the highest point of the
recess 115 in inner surfaces of each recess 115. That is, a
boundary portion between the first and second reflective sheets 160
and 165 may be a highest point portion of the recess 115.
[0113] The third reflective sheet 162 may be disposed adjacent to
the LED 173 rather than the first reflective sheet 160. The first
and second reflective sheets 160 and 165 may be disposed to
correspond to the light-transmitting sheet 180. As shown in FIG. 8,
both ends of the first reflective sheet 160 may be disposed in a
range of the angle R3 at a center of an emitting surface of the LED
173 as a starting point P, both ends of the second reflective sheet
165 may be disposed in a range of the angle R4 at a center of an
emitting surface of the LED 173 as a starting point P1, and both
ends of the third reflective sheet 162 may be disposed in a range
of the angle R5 at a center of an emitting surface of the LED 173
as a starting point P2.
[0114] As shown in FIGS. 9 and 10, a gap G1 between the
light-transmitting sheet 180 and the upper surface of the first
recess 15 becomes narrower toward the latching protrusion 125 with
respect to a center of the upper surface of the first recess 115.
Such a gap G1 may be a space in which light is mixed on the
light-transmitting sheet 180.
[0115] The first reflective sheet 160 may include a material
different from that of the second reflective sheet 165. The first
reflective sheet 160 may include a regular reflective sheet or a
mirror sheet, and the second reflective sheet 165 may include an
irregular reflective sheet or a white sheet. The first reflective
sheet 160 includes Ag and Al materials. The second reflective sheet
165 may be a white plastic material, for example, polycarbonate
(PC) or polypropylene (PP), or may include a nano-coating layer, or
a metal layer or a resin layer having a pattern formed thereon.
[0116] The third reflective sheet 162 may include an irregular
reflective sheet or a white sheet, or may include the same material
as that of the second reflective sheet 165. As another example, the
third reflective sheet 162 may include a regular reflective
sheet.
[0117] Here, as shown in FIGS. 11 and 12, when the third reflective
sheet 162 is an Ag sheet, the second side light L2 of the LED 173
is incident on and reflected by the third reflective sheet 162, and
light L10 and L11 reflected from the third reflective sheet 162 may
be irregularly reflected by the second reflective sheet 165. For
example, some light L10 of the light L10 and L11 reflected from the
third reflective sheet 162 may be sufficiently diffused by the gap
G1 with the light-transmitting sheet 180 and may be incident on the
light-transmitting sheet 180. However, when some light L11 of the
light L10 and L11 reflected from the third reflective sheet 162 is
diffused by the third reflective sheet 162 adjacent to the upper
end portion of the light-transmitting sheet 180, the light
diffusion is not performed by the narrow gap G1 and the light has a
non-uniform distribution in an upper end region B11 of the
light-transmitting sheet 180.
[0118] In an embodiment, by arranging the third reflective sheet
162 as the diffusion sheet or the irregular reflective sheet, even
when the gap G1 between the light-transmitting sheet 180 and the
second reflective sheet 165 becomes narrow, a non-uniform
distribution due to light reflected from the third reflective sheet
162 in the upper end region B11 of the light-transmitting sheet 180
can be improved. As another example, the third reflective sheet 162
may include a regular reflective sheet.
[0119] Referring to FIGS. 8 to 10, the first, second, and third
reflective sheets 160, 165, 162 according to an embodiment may
include curved surfaces having a plurality of inflection points,
and such a curved surface can reflect light to a desired optical
path.
[0120] The first and second reflective sheets 160 and 165 include a
material having a light reflectance of 90% or more, and light
incident by such light reflectance may be reflected without loss,
and thus a light extraction effect can be improved.
[0121] Here, at least one of the first and second reflective sheets
160 and 165 may be removed, and is not limited thereto.
[0122] When light reflected from the first and third reflective
sheets 160 and 162 is irregularly reflected by the second
reflective sheet 165 and is incident on the different regions B1,
B2, and B3, the light-transmitting sheets 180 and 182 diffuse and
transmit the incident light. Accordingly, it is possible to prevent
an occurrence of a bright line in the light-transmitting sheets 180
by the directly incident light and the indirectly incident light,
and to prevent glare.
[0123] A minimum distance between a center of an emitting surface
of the LED 173 and the first reflective sheet 160 may be 8 mm or
more, for example, in a range of 9 to 11 mm. When the minimum
distance between the center of the emitting surface of the LED 173
and the first reflective sheet 160 is smaller than the above range,
light out of a directional angle may be incident, and thus
improvement of the reflection efficiency may be insignificant. When
the minimum distance between the center of the emitting surface of
the LED 173 and the first reflective sheet 160 is larger than the
above range, a path of light reflection may be difficult to control
and leakage of the side light may occur.
[0124] A minimum distance between a center of an emitting surface
of the LED 173 and the third reflective sheet 162 may be 5 mm or
less, for example, in a range of 4 to 4.8 mm. When such a minimum
distance is smaller than the above range, the mounting of the
circuit board 171 may not be easy, and when such a minimum distance
is greater than the above range, leakage of the side light may
occur.
[0125] A minimum distance between a center of an emitting surface
of the LED 173 and the light-transmitting sheet 180 may be at least
twice a minimum distance between the LED 173 and the first
reflective sheet, for example, may range from 20 to 23 mm. When a
minimum distance between a center of the LED 173 and the
light-transmitting sheet 180 is larger than the above range, an
inclination becomes too large, and thus it is difficult to
uniformly control a light distribution. When the minimum distance
between the center of the LED 173 and the light-transmitting sheet
180 is smaller than the above range, hot spots or bright lines may
occur.
[0126] The first reflective sheet 160 may include a plurality of
reflective surfaces having different radii of curvature, and the
plurality of reflective surfaces may include curved surfaces having
a positive radius of curvature. The radius of curvature of the
plurality of reflective surfaces may become larger as a distance
from the LED 171 increases. The plurality of reflective surfaces
may be in at least three, and may include, for example, three to
five surfaces. When the number of the reflective surfaces is too
small, it is difficult to control a dispersion of light, and when
the number of the reflective surfaces is too large, luminous
intensity of the reflected light may be lowered. Each of the
plurality of reflective surfaces may reflect incident light to
different regions of the second reflective sheet 165.
[0127] The third reflective sheet 162 may be disposed between the
lower end portion of the light-transmitting sheet 180 and the LED
173. The third reflective sheet 162 may be disposed between the
lower end portion of the light-transmitting sheet 180 and the front
cover 155. The third reflective sheet 162 may include a plurality
of reflective surfaces having different radii of curvature. The
reflective surface of the third reflective sheet 162 may have a
larger radius of curvature as the surface becomes farther from the
LED 173.
[0128] Since the third reflective sheet 162 is disposed in a
parabolic shape in a region between the LED 173 and the
light-transmitting sheet 180 to reflect incident light to the
second reflective sheet 165 and the light-transmitting sheet 180,
the third reflective sheet 162 may uniformly irradiate light to the
light-transmitting sheet 180 to suppress a generation of a bright
line due to the light directly irradiated.
[0129] The first and third reflective sheets 160 and 165 may
irradiate light to the center region B2 of the light-transmitting
sheet 180, and thus in the center region B2, a bright line formed
by main light directly irradiated from the LED 173 can be reduced
by indirectly incident light.
[0130] Since the second reflective sheet 165 according to an
embodiment irregularly reflects light incident from the first
reflective sheet 160 and the LED 173 to uniformly irradiate the
center region B2 of the light-transmitting sheet 180 with the
light, it is possible to suppress a generation of a bright line due
to the light directly incident on the light-transmitting sheet 180
from the LED 173. In addition, light reflected by the third
reflective sheet 162 may be irregularly reflected by the second
reflective sheet 165 or may be irradiated onto the upper regions B1
and B2 of the light-transmitting sheet 180, so that a bright line
caused by light directly incident on the light-transmitting sheet
180 from the LED 173 may be removed.
[0131] The first to third reflective sheets 160, 165 and 162
improve uniformity of a distribution of light directly irradiated
to the light-transmitting sheets 180 and 182 by the LED 173,
thereby eliminating a bright line of a light-incident portion.
[0132] Reviewing a unified glare rating (UGR) of a lighting device
of the present invention, the UGR is 19 or less, indicating that a
user does not have any unpleasant glare. In the CIE standard, it is
classified that the user has an unpleasant feeling when the UGR is
21 or more.
[0133] Table 1 shows UGR, light efficiency, and light uniformity of
a lighting device according to an embodiment.
TABLE-US-00001 TABLE 1 UGR Endwise Crosswise (horizontal)
(portrait) Light efficiency Uniformity 18.2 19.0 85.1% 82.2%
[0134] Here, the size of the lighting device is 550 to 600
mm.times.550 to 600 mm, and a thickness or height ranges from 50 to
52 mm. The directional angle of the LED may also be in the range of
120 degrees.+-.5%.
[0135] Referring to FIGS. 1 and 13, a plurality of fastening
members 90 may be disposed at a predetermined interval in the
Z-axis direction in a center region of the housing 110, and the
fastening member 90 may protrude in a downward direction of the
Y-axis. A center side interval K1 may be narrower or wider than a
side interval K2 in the intervals K1 and K2 between the plurality
of fastening members 90, and is not limited thereto. The front
cover 155 may be fixed to the housing 110 together with the heat
radiator 150 by the fastening member 90.
[0136] FIGS. 14 to 16 are other examples of the front cover
according to an embodiment.
[0137] Referring to FIG. 14, the front cover 150 includes a fixing
frame 157 and a cover plate 156 extending in both lateral
directions below the fixing frame 157.
[0138] The fixing frame 157 has a fastening hole and may be
fastened to the housing 110 by a fastening part 19 together with
the heat radiator 150 of FIG. 14. The fixing frame 157 may have a
space 157A in which a lower portion of the fastening part 19 is
disposed.
[0139] An upper surface 70 of the cover plate 156 may have an
inclined surface and a lower surface thereof may provide a
plurality of concave-convex structures 71 and 72. The inclined
upper surface 70 may be extended so as to be in contact below the
lower end portions of the light-transmitting sheets 180 and 182 of
FIG. 12 toward an outward direction (for example, X-axis direction)
from a center of the cover plate 156. That is, an inclined angle of
the upper surface 70 of the cover plate 156 may be the same as an
inclined angle .theta.1 of the light-transmitting sheet 180 of FIG.
9. As another example, an outer side portion of a step structure
70A in the upper surface 70 of the cover plate 156 may be disposed
at the same angle as the inclined angle .theta.1 of the
light-transmitting sheet 180, and an inner side portion of the step
structure 70A may be disposed at an angle different from the
inclined angle .theta.1 of the light-transmitting sheet 180, for
example, may be disposed at a smaller or larger angle than the
angle .theta.1.
[0140] A lower portion of the cover plate 156 may include an inner
side region C1 and an outer side region C2 having the
concave-convex structures 71 and 72. The inner side region C1 may
be provided as a flat surface to secure rigidity at a center side
of the front cover 150. The flat inner side region C1 may be a
region overlapping with a region of the fixing frame 157 in a
vertical direction.
[0141] The step structure 70A may be provided at an outer side of
the upper surface 70 of the cover plate 156 of the front cover 155,
and the step structure 70A corresponds to the light
leakage-preventing protrusions 62 of the reflectors 153 and 153A of
the heat radiator 150 shown in FIG. 14 and thus light leakage
caused by the light-transmitting sheets 180 and 182 can be
reduced.
[0142] The outer side region C2 having the concave-convex
structures 71 and 72 may be disposed at an outer side of the inner
side region C1, may be a region not overlapping with the fixing
frame 157 in a vertical direction, and may be a region overlapping
with the recesses 115 and 115A shown in FIG. 12 in the vertical
direction. The outer side region C2 may become gradually thicker
toward an outward direction from a center of the cover plate
156.
[0143] In the concave-convex structures 71 and 72, the concave
portion 71 and the convex portion 72 may be alternately disposed. A
depth of the concave portion 71 in the concave-convex structures 71
and 72 may gradually increase toward an outward direction, and a
length of the convex portion 72 may gradually increase toward the
outward direction. When such a front cover 155 is provided with the
concave-convex structures 71 and 72 at a lower portion thereof and
is formed of a metal material, a heat dissipation surface area may
be increased. The concave portion 71 and the convex portion 72 may
be disposed to have the same length in the second Z-axis direction
as that of the front cover 155, and are not limited thereto.
[0144] Referring to FIG. 15, the front cover 155 includes a fixing
frame 157 and a cover plate 156 extending in opposite directions
below the fixing frame 157.
[0145] The cover plate 156 may have a concave portion 73 recessed
in an upward direction or in the direction of the heat radiator 150
in FIG. 14 toward a center of an inner side portion 74, and an
outer angle .theta.2 thereof may be disposed as an obtuse angle. An
outer side portion 75 of the cover plate 156 may be bent from the
inner side portion 74 and may include a step structure 75A. The
outer side portion 75 may be bent in a downward direction of the
lower end portions of the light-transmitting sheets 180 and 182
shown in FIG. 14.
[0146] The outer side portion 75 of the cover plate 156 provides a
step structure 75A. The step structure 75A may correspond to the
light leakage-preventing protrusions 62 of the reflectors 153 and
153A of the heat radiator 150 of FIG. 12, may facilitate an
insertion of the light-transmitting sheets 180 and 182, and thus
may prevent a light leakage.
[0147] Referring to FIG. 16, the front cover 155 includes a fixing
frame 157 and a cover plate 156 disposed below the fixing frame
157. Two frames 78 and 79 may be disposed spaced apart from each
other in parallel at the fixing frame 157 with a predetermined
space. A fastening part may be fastened to the spaced space 77.
[0148] As another example, the fixing frame 157 may include
latching ribs 78A and 79A, which are bent in an outward direction
from the frames 78 and 79, and the latching ribs 78A and 79A may be
latched and coupled to the lower frame 159B of the heat radiator
150 shown in FIG. 14.
[0149] As another example, the fixing frame 157 may have a hook
structure and be coupled to the heat radiator 150 of FIG. 14. As
another example, the heat radiator 150 of FIG. 14 may have a hook
structure and be coupled to the housing 110 via the hook
structure.
[0150] FIG. 18 is a view illustrating a latching jaw disposed on an
inner sidewall of a housing of FIG. 1, FIG. 19 is a perspective
view of a housing of FIG. 1 before a front cover is coupled, FIG.
20 is a view illustrating a latching jaw and a light-transmitting
sheet in an inner sidewall of a housing in FIG. 19, FIG. 21 is a
view illustrating a front cover and a light-transmitting sheet on a
latching jaw of a housing in FIG. 19, FIG. 22 is a partially
enlarged view of FIG. 21, FIG. 23 is a view illustrating an example
in which a light-transmitting sheet and a front cover are coupled
on a latching jaw in FIG. 19, and FIG. 24 is a view illustrating a
latching jaw of a housing, a light-transmitting sheet, and a front
cover in FIG. 23.
[0151] Referring to FIGS. 18 and 19, the housing 110 may include
first and second latching jaws 121 and 123 protruding from both
sidewalls of the Z-axis direction of the first and second recesses
115 and 115A. The first and second latching jaws 121 and 123 may be
disposed to face each other with respect to the second Z-axis
direction, and may extend from both sides of the connection portion
117 of the housing 110 to both sides of each of the first and
second latching protrusions 125 and 125A.
[0152] Each of the latching jaws 121 and 123 may include first
supporting portions 21 disposed on both sides of the first
light-transmitting sheet 180 in the second Z-axis direction, second
supporting portions 23 disposed on both sides of the second
light-transmitting sheet 182 in the second Z-axis direction, and a
light leakage-preventing portion 25 configured to protrude from a
region between the first and second supporting portions 21 and 23
and face one sides of lower end portions of the first and second
light-transmitting sheets 180 and 182.
[0153] A lower surface of the first supporting portion 21 may be
inclined along an inclined angle of the first light-transmitting
sheet 180, and a lower surface of the second supporting portion 23
may be inclined along an inclined angle of the second
light-transmitting sheet 182. The light leakage-preventing portion
25 may be formed in a shape to be in contact with an inner side of
the cover plate 156 of the front cover 155. The light
leakage-preventing portions 25 may be disposed below both sides of
the cover plate 156 in the second Z-axis direction.
[0154] The light leakage-preventing portion 25 protrudes from a
center of the housing 110 toward a lower surface of the housing 110
further than the first and second supporting portions 21 and
23.
[0155] As shown in FIGS. 21 to 24, a lower surface of the light
leakage-preventing portion 25 may be spaced apart from a lower
surface 114 of the housing 110 and the cover plate 156 of the front
cover 155 may be disposed in the spaced apart portion. Accordingly,
the cover plate 156 may extend to the lower surface of the light
leakage-preventing portion 25 of the latching jaws 121 and 123 and
to inner sides of the light-transmitting sheets 180 and 182,
thereby reducing light leakage.
[0156] The lower surface of the light leakage-preventing portion 25
of the latching jaws 121 and 123 may be formed along a surface of
the cover plate 156 of the front cover 155. As shown in FIGS. 21
and 22, the light leakage-preventing portion 25 includes a first
step structure 33 having a stepped height T2 with respect to the
lower surface of the first supporting portion 21, and a second step
structure 33A having a stepped height T2 with respect to the lower
surface of the second supporting portion 23.
[0157] Such first and second step structures 33 and 33A may have a
height T2 greater than a thickness T1 of the light-transmitting
sheets 180 and 182 and may face one sides of the light-transmitting
sheets 180 and 182. In addition, both sides of the front cover 155
covers the lower surface of the preventing portion 25 of the
latching jaws 121 and 123, a gap 35 between the preventing portion
25 and the first light-transmitting sheet 180, and a gap 35A
between the preventing portion 25 and the second light-transmitting
sheet 182. Accordingly, light leaked to one side through an inside
of the light-transmitting sheets 180 and 182 may be reflected by
the first and second step structures 33 and 33A, and may be blocked
by the front cover 155. Accordingly, it is possible to prevent an
occurrence of a light leakage via a region between the front cover
155 and the housing 110.
[0158] The cover plate 156 of the front cover 155 may be formed
with a stepped structure 53 on an outer side 52 of a lower surface
51, and the stepped structure 53 may be disposed in a region
between the light-transmitting sheets 180 and 182 and the
preventing portion 25 or disposed on the light leakage-preventing
protrusion 62 of the heat radiator 150, and thus light transmitted
through one side surface of the light-transmitting sheets 180 and
182 can be blocked.
[0159] Referring to FIGS. 20 to 22, the preventing portion 25 of
the latching jaws 121 and 123 and the heat dissipation protrusion
62 of the heat radiator 150 may be disposed on one side of a lower
end portion of the light-transmitting sheet 180. Since the
preventing portion 25 of the latching jaws 121 and 123 is disposed
on an outer sidewall of the housing 110, the preventing portion 25
of the latching jaws 121 and 123 may be disposed further outside
than the light leakage-preventing protrusion 62 of the heat
radiator 150.
[0160] One side of the light-transmitting sheets 180 and 182 may
have a gap G3 with the preventing portion 25 of the latching jaws
121 and 123 comparable to a predetermined gap 35 or 35A as shown in
FIGS. 20 and 24. As shown in FIGS. 20 and 23, one side of the
light-transmitting sheets 180 and 182 may be spaced apart from the
light leakage-preventing protrusion 62 of the heat radiator 150 at
a predetermined gap G2 and G2<G3.
[0161] As shown in FIGS. 20 to 24, the gap G3 of the gaps 35 and
35A between the preventing portion 25 of the latching jaws 121 and
123 and the light-transmitting sheets 180 and 182 may be disposed
to be wider than the gap G2 between the light leakage-preventing
protrusion 62 of the heat radiator 150 and the light-transmitting
sheets 180 and 182. A gap difference G3-G2 between the gaps 35 and
35A may be generated by an assembly tolerance and the preventing
portion 25 of the latching jaws 121 and 123 and the front cover 155
may suppress light leakage leaking into the gaps 35 and 35A.
[0162] An embodiment can prevent light leakage due to light leaking
through one side of a lower end portion of the light-transmitting
sheets 180 and 182 by the latching jaws 121 and 123 and the front
cover 155 as described above.
[0163] Referring to FIGS. 25 to 27, both end portions of the
light-transmitting sheets 180 and 182 may be disposed in a latching
groove 158 in FIG. 25 between the latching groove 118 of the
latching protrusions 125 and 125A and the front cover 155. For
example, upper end portions of the light-transmitting sheets 180
and 182 may be disposed on the latching protrusions 125 and 125A,
respectively, and lower end portions thereof may be disposed on the
cover plate 156 of the front cover 155.
[0164] In the light-transmitting sheets 180 and 182, both edges in
the first X-axis direction are slidably coupled along the latching
protrusions 125 and 125A and the cover plate 156, and both edges in
the second Z-axis direction of the light-transmitting sheets 180
and 182 may be placed below the first and second latching jaws 121
and 123 shown in FIG. 18.
[0165] As shown in FIG. 27, the latching groove 118 on the latching
protrusion 125 is formed to have a height E1 greater than a
thickness T1 of the light-transmitting sheet 180, and thus the
light-transmitting sheet 180 can be inserted easily. In addition,
the latching protrusion 125 may protrude at a predetermined
distance E2 in the direction of the first recess 115, and such a
distance E2 may be greater than the height E1, and thus the
light-transmitting sheet 180 can be prevented from being
separated.
[0166] The upper and lower end portions of the light-transmitting
sheets 180 and 182 are supported by and in close contact with the
latching jaws 121 and 123 and the cover plate 156, thereby
preventing light leakage from occurring.
[0167] <Light Emitting Device Package>
[0168] FIG. 27 is a sectional view showing a light emitting diode
according to the embodiment.
[0169] Referring to FIG. 27, the light emitting diode 200 includes
a body 210; first and second lead electrodes 211 and 213, at least
portions of which are disposed in the body 210, a light-emitting
device 101 electrically connected to the first and second lead
electrodes 211 and 212 on the body 210, and a molding member 220
surrounding the light emitting device 101.
[0170] The body 210 may be formed of at least one of a silicon
material, a synthetic resin material and a metallic material. The
body 210 may include a cavity formed therein and a reflective
portion 215 having an inclined surface at the periphery
thereof.
[0171] The first lead electrode 211 and the second lead electrode
213 are electrically separated from each other, and are formed to
pass through the body 210. That is, the inner side portions of the
first and second lead electrodes 211 and 212 may be disposed in the
cavity and the other portions of the first and second lead
electrodes 211 and 212 may be disposed at an outside of the body
210.
[0172] The first lead electrode 211 and the second lead electrode
212 provide power to the light-emitting device 100 Also, the first
lead electrode 211 and the second lead electrode 213 reflect the
light emitted from the light emitting device 101, thus improving
the light emitting efficiency. Also, the first lead electrode 211
and the second lead electrode 213 may serve to discharge the heat
generated from the light emitting device 101.
[0173] The light emitting device 101 may be disposed on the body
210, or may be formed on the first lead electrode 211 and/or the
second lead electrode 212. The light emitting device 101 may be
arranged as at least one LED (Light Emitting Diode) chip. The LED
chip may include a light emitting diode in a visible light band
such as red, green, blue or white, or a UV light emitting diode
that emits ultraviolet (UV) light. A phosphor layer may be further
disposed on the surface of the light emitting device 101, but the
present invention is not limited thereto.
[0174] The wire 216 of the light emitting device 101 may be
electrically connected to at least one of the first and second lead
electrodes 211 and 212, but the embodiment is not limited
thereto.
[0175] The molding member 220 may surround the light-emitting
device 101 to protect the light emitting device 101. Also, the
molding member 220 may include a fluorescent material to change the
wavelength of light emitted from the light emitting device 101. The
upper surface of the molding member 220 may be flat, concave or
convex. The upper surface of the molding member 220 or the cavity
region may be the light emitting surface according to the
embodiment, but the present invention is not limited thereto.
[0176] A lens may be disposed on the molding member 220, but the
present invention is not limited thereto.
[0177] The light emitting diode 200 may be a blue light emitting
device or a white light emitting device having a high color
rendering index (CRI). The light emitting diode may be a light
emitting device that emits white light by molding a synthetic resin
containing a phosphor on a blue light emitting chip. The phosphor
may include at least one of a garnet (YAG, TAG), a silicate, a
nitride, and an oxy-nitride.
[0178] The features, structures, effects and the like described in
the embodiments are included in at least one embodiment of the
present invention, and are not necessarily limited to only one
embodiment. Furthermore, the features, structures, effects and the
like illustrated in the embodiments can be combined and modified by
other persons skilled in the art to which the embodiments belong.
Therefore, it is to be understood that the present invention is not
limited to these embodiments.
[0179] Although embodiments have been described with reference to a
number of illustrative embodiments thereof, it should be understood
that numerous other modifications and embodiments can be devised by
those skilled in the art that will fall within the spirit and scope
of the principles of this disclosure. More particularly, various
variations and modifications are possible in the component parts
and/or arrangements of the subject combination arrangement within
the scope of the disclosure, the drawings and the appended claims.
In addition to variations and modifications in the component parts
and/or arrangements, alternative uses will also be apparent to
those skilled in the art.
INDUSTRIAL APPLICABILITY
[0180] An embodiment may be applied to a lighting device for a flat
panel.
[0181] An embodiment may be applied to a lighting device for a flat
panel having a light emitting diode (LED).
* * * * *